Conventionally, as a deep-drawing packaging machine used for packaging, for example, food, a deep-drawing packaging machine 1 as shown in FIG. 6 has been known. The deep-drawing packaging machine 1 is basically configured to manufacture containers 5, in which, for example, food ingredients are packaged, by placing, for example, the food ingredients (not shown) in a bottom film 2 molded in recessed shapes, then covering them with a top film 3, and sealing (hermetically closing) them by a sealing device 4.
In FIG. 6, a molding device for molding the bottom film 2 into the recessed shapes by molds is represented by 6, an unprocessed roll of the bottom film 2 is represented by 7, an unprocessed roll of the top film 3 is represented by 8, a cross-cutter device which cuts the sealed bottom film 2 and top film. 3 in the direction perpendicular to the direction in which they are carried is represented by 9, a length cutter device which cuts the sealed bottom film 2 and top film 3 in parallel to the direction in which they are carried is represented by 10, and an infeed roller for guiding the bottom film 2 to the molding device 6 is represented by 11.
FIG. 7 shows, in an enlarged manner, the vicinity of an infeed roller 11 of the deep-drawing packaging machine 1. As shown in the drawing, the deep-drawing packaging machine 1 has, as a carrying device which carries the bottom film 2, clamping tabs 12 which clamp both-side edges of the bottom film 2, endless chains 13 to which the clamping tabs 12 are fixed, and sprockets 14 around which the endless chains 13 are suspended. The sprockets 14 are configured to be rotated by drive of a motor, which is not shown here, thereby carrying the bottom film 2 to the direction of an arrow in the drawing.
FIG. 8 shows details of the clamping tabs 12 and the endless chain 13. As shown in the drawing, the clamping tab 12 consists of an upper tab 15, a lower tab 16, and a spring 17 and is configured so that, when the upper tab 15 and the lower tab 16 are brought into close contact with each other by the biasing action of the spring 17, the clamping tab 12 is closed and clamps the bottom film 2. Moreover, as shown in FIG. 7, the clamping tab 12 is configured to open the upper tab 15 and the lower tab 16 at the position of the sprocket 14 by an action of a cam plate (not shown) provided to be coaxial with the sprocket 14. As shown in FIG. 7 and FIG. 9, in this process, the clamping tab 12 is configured so that only the upper tab 15 is opened while it is moved toward outside.
The bottom film 2 is configured so that the both-side edges thereof are clamped by the clamping tabs 12 having the configuration as described above, after the bottom film 2 is molded into recessed shapes by the molding device 6, for example food ingredients (not shown) are placed therein, then, they are covered with the top film 3 as shown in FIG. 6, and they are sealed by the sealing device 4. In this process, as shown in FIG. 10, after the bottom film 2 is clamped at the position of the sprockets 14, the clamping tabs 12 are configured to carry the bottom film 2 while continuing clamping to the position of the length cutter device 10. Moreover, before the top film 3 is carried to the sealing device 4, as well as the bottom film 2, the top film 3 is configured so that the both edges thereof are clamped by the clamping tabs 12, and the top film 3 is then carried to the sealing device 4 together with the bottom film 2, which has undergone recessed-shape molding.
The sealing device 4 is configured to seal the bottom film 2 and the top film 3 in the steps shown in FIG. 11. As shown in the drawing, the sealing device 4 basically consists of an upper mold 4a, a lower mold 4b, and a sealing hot plate 18.
First, as shown in (A) of the drawing, the bottom film 2 and the top film 3 clamped by the clamping tabs 12 are carried to the part between the upper mold 4a and the lower mold 4b, which are opened to the upper and lower sides. Then, as shown in (B) of the drawing, the lower mold 4b is moved up, the upper mold 4a and the lower mold 4b are closed, and, at the same time with that, air is removed from ventilation holes 19a and 19b provided on the upper and lower molds 4a and 4b, respectively, to bring the interiors of the containers 5 into a vacuum state.
Then, as shown in (C) of the drawing, the sealing hot plate 18 is moved down, the bottom film 2 and the top film 3 are sealed by thermal welding, and sealing of the containers 5 is carried out. Then, as the sealing hot plate 18 is moved up, the lower mold 4b is moved down, and the upper mold 4a and the lower mold 4b are opened and are returned to the state of (A) of the drawing. These steps of (A) to (C) of FIG. 11 are repeated to carry out the sealing step by the sealing device 4.
In the step of (B) of the drawing, as shown by a plurality of small arrows, the air in the containers 5 is configured to be removed from the vicinities of the both sides of the bottom film 2 to the outside the containers 5 through ventilation pipes 20 provided in the lower mold 4b. Herein, as shown in FIG. 12, the bottom film 2 is provided with a plurality of punch holes 21 along the both-side edges of the bottom film 2, and the positions of the punch holes 21 and the positions of open ends 20a of the ventilation pipes 20 are configured to match each other. Therefore, the air in the containers 5 is configured to flow to the ventilation pipes 20 through the punch holes 21.
The punch holes 21 are configured to be formed in the bottom film 2 by, for example, punching gears (not shown) provided to be coaxial with the sprockets 14 before the bottom film 2 is carried to the sealing device 4. Normally, the punching hole shapes thereof are designed so that punching scraps of punching are not dropped when the punch holes 21 are formed. Furthermore, the air in the containers 5 is not removed from the ventilation holes 19a of the upper mold 4a because of the presence of the top film 3; however, in order to maintain the pressure balance around the containers 5, degassing is configured to be carried out also from the ventilation holes 19a. 
Incidentally, when the containers 5 are to be manufactured by using the deep-drawing packaging machine 1 having such a configuration, it has been essential to provide the punch holes 21. This is for a reason that, if the punch holes 21 are not provided, air cannot be removed from the containers 5. Therefore, in order to ensure the space for providing the punch holes 21, conventionally, extra parts having a predetermined width have been provided at the both-side edges of the bottom film 2 as shown by S of FIG. 12. The extra parts S are unnecessary in the containers 5 and are therefore have to be removed before the containers 5 are completed. Normally, the extra parts S have been cut off as scraps by the length cutter device 10 in manufacturing.
However, since the scraps cut off in this manner have to be processed as wastes, there has been a problem that the processing takes labor and time.
Under such circumstances, the inventor of the present application has diligently studied the methods and means that can solve the above described problem. As a result, the inventor of the present application has found out that the above described problem can be solved when the deep-drawing packaging machine is configured so that the clamping tabs are moved while the clamping tabs are separated from the bottom film 2 and the top film 3 at predetermined positions and accomplished the present invention.
When the inventor and applicant of the present application researched past patent literatures, etc. before application of the present invention, below literatures have been found about deep-drawing packaging machines; however, patent literatures describing technical ideas, etc. related to the present invention in detail were not found.